1. Each letter is paired with each of the other letters to produce all the permutations of 2 letters. There are 6×5 = 30 of them.
FA FB FR FI FC .. A.F AB AR AI AC .. BF BA BR BI BC .. RF RA RB RI RC .. IF IA IB IR IC .. CF CA CB CR CI
2. The linear regression function of a graphing calculator can be used to find the line of best fit. Generally, this involves entering the given coordinates and invoking the appropriate regression calculation.
... calories ≈ 13.9×(fat grams) + 191.3
